Given: pH = 5, so [H+]=10−5 M; G = 4×10−5 S; A = 1 cm²; l = 15 cm
Cell constant = l/A = 15 cm⁻¹
Specific conductivity: κ=G×(l/A)=4×10−5×15=6×10−4 S/cm
For weak acid HX: [H+]=Cα=10−5 M
Using κ=1000Cα×Λ°m
Λ°m=Cα1000×κ=10−51000×6×10−4=6×104 S cm² mol⁻¹
Converting: Λ°m=6×104×10−4=6 S m² mol⁻¹